Wafer bump and/or solder ball height and coplanarity inspections are commonly carried out to check for any significant unevenness and missing bumps or balls, because such defects in a component mean loss of electrical contact, leading to component failure.
Current methods include taking multiple images of a plurality of bumps on a surface of a component from different viewpoints and angles, and performing triangulation calculations on related measurements of the images to determine a three dimensional position of each bump with reference to a pre-calculated calibration plane. This is achieved by holding the component stationary while multiple exposures are made in succession to capture images from different angles using multiple cameras, or using a single camera with multiple light sources aimed at different angles on the component. Such methods are not suitable for inspecting every component produced as they need the component to be stopped momentarily for image capturing —adding to total production time and hence increasing production costs. Since only a sample group of each production batch will be inspected, defective components will still get passed if they do not happen to be in the sample group. Side view images captured by such methods are also limited in depth of view, requiring multiple exposures to be made in order to inspect the whole component if the component size is greater than the depth of view. Again, this increases inspection time.